Technology

There ought not to be something in the whole universe
that a man can't poke his nose in to.
That's the way we're built
and I assume there's a good reason for it.
-Robert A. Heinlein

Much of the technology necessary to get to Mars has already been invented, and is already either in use or is being tested. "Technology" is a very wide definition of all the stuff we’ll need, so I’ve broken it in to several sections.